1 /* $OpenBSD: client.c,v 1.143 2020/04/27 08:35:09 nicm Exp $ */ 2 3 /* 4 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER 15 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 16 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/socket.h> 21 #include <sys/un.h> 22 #include <sys/wait.h> 23 24 #include <errno.h> 25 #include <event.h> 26 #include <fcntl.h> 27 #include <imsg.h> 28 #include <signal.h> 29 #include <stdlib.h> 30 #include <string.h> 31 #include <unistd.h> 32 33 #include "tmux.h" 34 35 static struct tmuxproc *client_proc; 36 static struct tmuxpeer *client_peer; 37 static int client_flags; 38 static enum { 39 CLIENT_EXIT_NONE, 40 CLIENT_EXIT_DETACHED, 41 CLIENT_EXIT_DETACHED_HUP, 42 CLIENT_EXIT_LOST_TTY, 43 CLIENT_EXIT_TERMINATED, 44 CLIENT_EXIT_LOST_SERVER, 45 CLIENT_EXIT_EXITED, 46 CLIENT_EXIT_SERVER_EXITED, 47 } client_exitreason = CLIENT_EXIT_NONE; 48 static int client_exitflag; 49 static int client_exitval; 50 static enum msgtype client_exittype; 51 static const char *client_exitsession; 52 static const char *client_execshell; 53 static const char *client_execcmd; 54 static int client_attached; 55 static struct client_files client_files = RB_INITIALIZER(&client_files); 56 57 static __dead void client_exec(const char *,const char *); 58 static int client_get_lock(char *); 59 static int client_connect(struct event_base *, const char *, int); 60 static void client_send_identify(const char *, const char *, int); 61 static void client_signal(int); 62 static void client_dispatch(struct imsg *, void *); 63 static void client_dispatch_attached(struct imsg *); 64 static void client_dispatch_wait(struct imsg *); 65 static const char *client_exit_message(void); 66 67 /* 68 * Get server create lock. If already held then server start is happening in 69 * another client, so block until the lock is released and return -2 to 70 * retry. Return -1 on failure to continue and start the server anyway. 71 */ 72 static int 73 client_get_lock(char *lockfile) 74 { 75 int lockfd; 76 77 log_debug("lock file is %s", lockfile); 78 79 if ((lockfd = open(lockfile, O_WRONLY|O_CREAT, 0600)) == -1) { 80 log_debug("open failed: %s", strerror(errno)); 81 return (-1); 82 } 83 84 if (flock(lockfd, LOCK_EX|LOCK_NB) == -1) { 85 log_debug("flock failed: %s", strerror(errno)); 86 if (errno != EAGAIN) 87 return (lockfd); 88 while (flock(lockfd, LOCK_EX) == -1 && errno == EINTR) 89 /* nothing */; 90 close(lockfd); 91 return (-2); 92 } 93 log_debug("flock succeeded"); 94 95 return (lockfd); 96 } 97 98 /* Connect client to server. */ 99 static int 100 client_connect(struct event_base *base, const char *path, int flags) 101 { 102 struct sockaddr_un sa; 103 size_t size; 104 int fd, lockfd = -1, locked = 0; 105 char *lockfile = NULL; 106 107 memset(&sa, 0, sizeof sa); 108 sa.sun_family = AF_UNIX; 109 size = strlcpy(sa.sun_path, path, sizeof sa.sun_path); 110 if (size >= sizeof sa.sun_path) { 111 errno = ENAMETOOLONG; 112 return (-1); 113 } 114 log_debug("socket is %s", path); 115 116 retry: 117 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 118 return (-1); 119 120 log_debug("trying connect"); 121 if (connect(fd, (struct sockaddr *)&sa, sizeof sa) == -1) { 122 log_debug("connect failed: %s", strerror(errno)); 123 if (errno != ECONNREFUSED && errno != ENOENT) 124 goto failed; 125 if (~flags & CLIENT_STARTSERVER) 126 goto failed; 127 close(fd); 128 129 if (!locked) { 130 xasprintf(&lockfile, "%s.lock", path); 131 if ((lockfd = client_get_lock(lockfile)) < 0) { 132 log_debug("didn't get lock (%d)", lockfd); 133 134 free(lockfile); 135 lockfile = NULL; 136 137 if (lockfd == -2) 138 goto retry; 139 } 140 log_debug("got lock (%d)", lockfd); 141 142 /* 143 * Always retry at least once, even if we got the lock, 144 * because another client could have taken the lock, 145 * started the server and released the lock between our 146 * connect() and flock(). 147 */ 148 locked = 1; 149 goto retry; 150 } 151 152 if (lockfd >= 0 && unlink(path) != 0 && errno != ENOENT) { 153 free(lockfile); 154 close(lockfd); 155 return (-1); 156 } 157 fd = server_start(client_proc, flags, base, lockfd, lockfile); 158 } 159 160 if (locked && lockfd >= 0) { 161 free(lockfile); 162 close(lockfd); 163 } 164 setblocking(fd, 0); 165 return (fd); 166 167 failed: 168 if (locked) { 169 free(lockfile); 170 close(lockfd); 171 } 172 close(fd); 173 return (-1); 174 } 175 176 /* Get exit string from reason number. */ 177 const char * 178 client_exit_message(void) 179 { 180 static char msg[256]; 181 182 switch (client_exitreason) { 183 case CLIENT_EXIT_NONE: 184 break; 185 case CLIENT_EXIT_DETACHED: 186 if (client_exitsession != NULL) { 187 xsnprintf(msg, sizeof msg, "detached " 188 "(from session %s)", client_exitsession); 189 return (msg); 190 } 191 return ("detached"); 192 case CLIENT_EXIT_DETACHED_HUP: 193 if (client_exitsession != NULL) { 194 xsnprintf(msg, sizeof msg, "detached and SIGHUP " 195 "(from session %s)", client_exitsession); 196 return (msg); 197 } 198 return ("detached and SIGHUP"); 199 case CLIENT_EXIT_LOST_TTY: 200 return ("lost tty"); 201 case CLIENT_EXIT_TERMINATED: 202 return ("terminated"); 203 case CLIENT_EXIT_LOST_SERVER: 204 return ("server exited unexpectedly"); 205 case CLIENT_EXIT_EXITED: 206 return ("exited"); 207 case CLIENT_EXIT_SERVER_EXITED: 208 return ("server exited"); 209 } 210 return ("unknown reason"); 211 } 212 213 /* Exit if all streams flushed. */ 214 static void 215 client_exit(void) 216 { 217 struct client_file *cf; 218 size_t left; 219 int waiting = 0; 220 221 RB_FOREACH (cf, client_files, &client_files) { 222 if (cf->event == NULL) 223 continue; 224 left = EVBUFFER_LENGTH(cf->event->output); 225 if (left != 0) { 226 waiting++; 227 log_debug("file %u %zu bytes left", cf->stream, left); 228 } 229 } 230 if (waiting == 0) 231 proc_exit(client_proc); 232 } 233 234 /* Client main loop. */ 235 int 236 client_main(struct event_base *base, int argc, char **argv, int flags, int feat) 237 { 238 struct cmd_parse_result *pr; 239 struct msg_command *data; 240 int fd, i; 241 const char *ttynam, *cwd; 242 pid_t ppid; 243 enum msgtype msg; 244 struct termios tio, saved_tio; 245 size_t size; 246 247 /* Ignore SIGCHLD now or daemon() in the server will leave a zombie. */ 248 signal(SIGCHLD, SIG_IGN); 249 250 /* Set up the initial command. */ 251 if (shell_command != NULL) { 252 msg = MSG_SHELL; 253 flags |= CLIENT_STARTSERVER; 254 } else if (argc == 0) { 255 msg = MSG_COMMAND; 256 flags |= CLIENT_STARTSERVER; 257 } else { 258 msg = MSG_COMMAND; 259 260 /* 261 * It sucks parsing the command string twice (in client and 262 * later in server) but it is necessary to get the start server 263 * flag. 264 */ 265 pr = cmd_parse_from_arguments(argc, argv, NULL); 266 if (pr->status == CMD_PARSE_SUCCESS) { 267 if (cmd_list_any_have(pr->cmdlist, CMD_STARTSERVER)) 268 flags |= CLIENT_STARTSERVER; 269 cmd_list_free(pr->cmdlist); 270 } else 271 free(pr->error); 272 } 273 274 /* Save the flags. */ 275 client_flags = flags; 276 277 /* Create client process structure (starts logging). */ 278 client_proc = proc_start("client"); 279 proc_set_signals(client_proc, client_signal); 280 281 /* Initialize the client socket and start the server. */ 282 fd = client_connect(base, socket_path, client_flags); 283 if (fd == -1) { 284 if (errno == ECONNREFUSED) { 285 fprintf(stderr, "no server running on %s\n", 286 socket_path); 287 } else { 288 fprintf(stderr, "error connecting to %s (%s)\n", 289 socket_path, strerror(errno)); 290 } 291 return (1); 292 } 293 client_peer = proc_add_peer(client_proc, fd, client_dispatch, NULL); 294 295 /* Save these before pledge(). */ 296 if ((cwd = find_cwd()) == NULL && (cwd = find_home()) == NULL) 297 cwd = "/"; 298 if ((ttynam = ttyname(STDIN_FILENO)) == NULL) 299 ttynam = ""; 300 301 /* 302 * Drop privileges for client. "proc exec" is needed for -c and for 303 * locking (which uses system(3)). 304 * 305 * "tty" is needed to restore termios(4) and also for some reason -CC 306 * does not work properly without it (input is not recognised). 307 * 308 * "sendfd" is dropped later in client_dispatch_wait(). 309 */ 310 if (pledge( 311 "stdio rpath wpath cpath unix sendfd proc exec tty", 312 NULL) != 0) 313 fatal("pledge failed"); 314 315 /* Free stuff that is not used in the client. */ 316 if (ptm_fd != -1) 317 close(ptm_fd); 318 options_free(global_options); 319 options_free(global_s_options); 320 options_free(global_w_options); 321 environ_free(global_environ); 322 323 /* Set up control mode. */ 324 if (client_flags & CLIENT_CONTROLCONTROL) { 325 if (tcgetattr(STDIN_FILENO, &saved_tio) != 0) { 326 fprintf(stderr, "tcgetattr failed: %s\n", 327 strerror(errno)); 328 return (1); 329 } 330 cfmakeraw(&tio); 331 tio.c_iflag = ICRNL|IXANY; 332 tio.c_oflag = OPOST|ONLCR; 333 tio.c_lflag = NOKERNINFO; 334 tio.c_cflag = CREAD|CS8|HUPCL; 335 tio.c_cc[VMIN] = 1; 336 tio.c_cc[VTIME] = 0; 337 cfsetispeed(&tio, cfgetispeed(&saved_tio)); 338 cfsetospeed(&tio, cfgetospeed(&saved_tio)); 339 tcsetattr(STDIN_FILENO, TCSANOW, &tio); 340 } 341 342 /* Send identify messages. */ 343 client_send_identify(ttynam, cwd, feat); 344 345 /* Send first command. */ 346 if (msg == MSG_COMMAND) { 347 /* How big is the command? */ 348 size = 0; 349 for (i = 0; i < argc; i++) 350 size += strlen(argv[i]) + 1; 351 if (size > MAX_IMSGSIZE - (sizeof *data)) { 352 fprintf(stderr, "command too long\n"); 353 return (1); 354 } 355 data = xmalloc((sizeof *data) + size); 356 357 /* Prepare command for server. */ 358 data->argc = argc; 359 if (cmd_pack_argv(argc, argv, (char *)(data + 1), size) != 0) { 360 fprintf(stderr, "command too long\n"); 361 free(data); 362 return (1); 363 } 364 size += sizeof *data; 365 366 /* Send the command. */ 367 if (proc_send(client_peer, msg, -1, data, size) != 0) { 368 fprintf(stderr, "failed to send command\n"); 369 free(data); 370 return (1); 371 } 372 free(data); 373 } else if (msg == MSG_SHELL) 374 proc_send(client_peer, msg, -1, NULL, 0); 375 376 /* Start main loop. */ 377 proc_loop(client_proc, NULL); 378 379 /* Run command if user requested exec, instead of exiting. */ 380 if (client_exittype == MSG_EXEC) { 381 if (client_flags & CLIENT_CONTROLCONTROL) 382 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 383 client_exec(client_execshell, client_execcmd); 384 } 385 386 /* Print the exit message, if any, and exit. */ 387 if (client_attached) { 388 if (client_exitreason != CLIENT_EXIT_NONE) 389 printf("[%s]\n", client_exit_message()); 390 391 ppid = getppid(); 392 if (client_exittype == MSG_DETACHKILL && ppid > 1) 393 kill(ppid, SIGHUP); 394 } else if (client_flags & CLIENT_CONTROLCONTROL) { 395 if (client_exitreason != CLIENT_EXIT_NONE) 396 printf("%%exit %s\n", client_exit_message()); 397 else 398 printf("%%exit\n"); 399 printf("\033\\"); 400 tcsetattr(STDOUT_FILENO, TCSAFLUSH, &saved_tio); 401 } else if (client_exitreason != CLIENT_EXIT_NONE) 402 fprintf(stderr, "%s\n", client_exit_message()); 403 setblocking(STDIN_FILENO, 1); 404 return (client_exitval); 405 } 406 407 /* Send identify messages to server. */ 408 static void 409 client_send_identify(const char *ttynam, const char *cwd, int feat) 410 { 411 const char *s; 412 char **ss; 413 size_t sslen; 414 int fd, flags = client_flags; 415 pid_t pid; 416 417 proc_send(client_peer, MSG_IDENTIFY_FLAGS, -1, &flags, sizeof flags); 418 419 if ((s = getenv("TERM")) == NULL) 420 s = ""; 421 proc_send(client_peer, MSG_IDENTIFY_TERM, -1, s, strlen(s) + 1); 422 proc_send(client_peer, MSG_IDENTIFY_FEATURES, -1, &feat, sizeof feat); 423 424 proc_send(client_peer, MSG_IDENTIFY_TTYNAME, -1, ttynam, 425 strlen(ttynam) + 1); 426 proc_send(client_peer, MSG_IDENTIFY_CWD, -1, cwd, strlen(cwd) + 1); 427 428 if ((fd = dup(STDIN_FILENO)) == -1) 429 fatal("dup failed"); 430 proc_send(client_peer, MSG_IDENTIFY_STDIN, fd, NULL, 0); 431 432 pid = getpid(); 433 proc_send(client_peer, MSG_IDENTIFY_CLIENTPID, -1, &pid, sizeof pid); 434 435 for (ss = environ; *ss != NULL; ss++) { 436 sslen = strlen(*ss) + 1; 437 if (sslen > MAX_IMSGSIZE - IMSG_HEADER_SIZE) 438 continue; 439 proc_send(client_peer, MSG_IDENTIFY_ENVIRON, -1, *ss, sslen); 440 } 441 442 proc_send(client_peer, MSG_IDENTIFY_DONE, -1, NULL, 0); 443 } 444 445 /* File write error callback. */ 446 static void 447 client_write_error_callback(__unused struct bufferevent *bev, 448 __unused short what, void *arg) 449 { 450 struct client_file *cf = arg; 451 452 log_debug("write error file %d", cf->stream); 453 454 bufferevent_free(cf->event); 455 cf->event = NULL; 456 457 close(cf->fd); 458 cf->fd = -1; 459 460 if (client_exitflag) 461 client_exit(); 462 } 463 464 /* File write callback. */ 465 static void 466 client_write_callback(__unused struct bufferevent *bev, void *arg) 467 { 468 struct client_file *cf = arg; 469 470 if (cf->closed && EVBUFFER_LENGTH(cf->event->output) == 0) { 471 bufferevent_free(cf->event); 472 close(cf->fd); 473 RB_REMOVE(client_files, &client_files, cf); 474 file_free(cf); 475 } 476 477 if (client_exitflag) 478 client_exit(); 479 } 480 481 /* Open write file. */ 482 static void 483 client_write_open(void *data, size_t datalen) 484 { 485 struct msg_write_open *msg = data; 486 const char *path; 487 struct msg_write_ready reply; 488 struct client_file find, *cf; 489 const int flags = O_NONBLOCK|O_WRONLY|O_CREAT; 490 int error = 0; 491 492 if (datalen < sizeof *msg) 493 fatalx("bad MSG_WRITE_OPEN size"); 494 if (datalen == sizeof *msg) 495 path = "-"; 496 else 497 path = (const char *)(msg + 1); 498 log_debug("open write file %d %s", msg->stream, path); 499 500 find.stream = msg->stream; 501 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 502 cf = file_create(NULL, msg->stream, NULL, NULL); 503 RB_INSERT(client_files, &client_files, cf); 504 } else { 505 error = EBADF; 506 goto reply; 507 } 508 if (cf->closed) { 509 error = EBADF; 510 goto reply; 511 } 512 513 cf->fd = -1; 514 if (msg->fd == -1) 515 cf->fd = open(path, msg->flags|flags, 0644); 516 else { 517 if (msg->fd != STDOUT_FILENO && msg->fd != STDERR_FILENO) 518 errno = EBADF; 519 else { 520 cf->fd = dup(msg->fd); 521 if (~client_flags & CLIENT_CONTROL) 522 close(msg->fd); /* can only be used once */ 523 } 524 } 525 if (cf->fd == -1) { 526 error = errno; 527 goto reply; 528 } 529 530 cf->event = bufferevent_new(cf->fd, NULL, client_write_callback, 531 client_write_error_callback, cf); 532 bufferevent_enable(cf->event, EV_WRITE); 533 goto reply; 534 535 reply: 536 reply.stream = msg->stream; 537 reply.error = error; 538 proc_send(client_peer, MSG_WRITE_READY, -1, &reply, sizeof reply); 539 } 540 541 /* Write to client file. */ 542 static void 543 client_write_data(void *data, size_t datalen) 544 { 545 struct msg_write_data *msg = data; 546 struct client_file find, *cf; 547 size_t size = datalen - sizeof *msg; 548 549 if (datalen < sizeof *msg) 550 fatalx("bad MSG_WRITE size"); 551 find.stream = msg->stream; 552 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 553 fatalx("unknown stream number"); 554 log_debug("write %zu to file %d", size, cf->stream); 555 556 if (cf->event != NULL) 557 bufferevent_write(cf->event, msg + 1, size); 558 } 559 560 /* Close client file. */ 561 static void 562 client_write_close(void *data, size_t datalen) 563 { 564 struct msg_write_close *msg = data; 565 struct client_file find, *cf; 566 567 if (datalen != sizeof *msg) 568 fatalx("bad MSG_WRITE_CLOSE size"); 569 find.stream = msg->stream; 570 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) 571 fatalx("unknown stream number"); 572 log_debug("close file %d", cf->stream); 573 574 if (cf->event == NULL || EVBUFFER_LENGTH(cf->event->output) == 0) { 575 if (cf->event != NULL) 576 bufferevent_free(cf->event); 577 if (cf->fd != -1) 578 close(cf->fd); 579 RB_REMOVE(client_files, &client_files, cf); 580 file_free(cf); 581 } 582 } 583 584 /* File read callback. */ 585 static void 586 client_read_callback(__unused struct bufferevent *bev, void *arg) 587 { 588 struct client_file *cf = arg; 589 void *bdata; 590 size_t bsize; 591 struct msg_read_data *msg; 592 size_t msglen; 593 594 msg = xmalloc(sizeof *msg); 595 for (;;) { 596 bdata = EVBUFFER_DATA(cf->event->input); 597 bsize = EVBUFFER_LENGTH(cf->event->input); 598 599 if (bsize == 0) 600 break; 601 if (bsize > MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg) 602 bsize = MAX_IMSGSIZE - IMSG_HEADER_SIZE - sizeof *msg; 603 log_debug("read %zu from file %d", bsize, cf->stream); 604 605 msglen = (sizeof *msg) + bsize; 606 msg = xrealloc(msg, msglen); 607 msg->stream = cf->stream; 608 memcpy(msg + 1, bdata, bsize); 609 proc_send(client_peer, MSG_READ, -1, msg, msglen); 610 611 evbuffer_drain(cf->event->input, bsize); 612 } 613 free(msg); 614 } 615 616 /* File read error callback. */ 617 static void 618 client_read_error_callback(__unused struct bufferevent *bev, 619 __unused short what, void *arg) 620 { 621 struct client_file *cf = arg; 622 struct msg_read_done msg; 623 624 log_debug("read error file %d", cf->stream); 625 626 msg.stream = cf->stream; 627 msg.error = 0; 628 proc_send(client_peer, MSG_READ_DONE, -1, &msg, sizeof msg); 629 630 bufferevent_free(cf->event); 631 close(cf->fd); 632 RB_REMOVE(client_files, &client_files, cf); 633 file_free(cf); 634 } 635 636 /* Open read file. */ 637 static void 638 client_read_open(void *data, size_t datalen) 639 { 640 struct msg_read_open *msg = data; 641 const char *path; 642 struct msg_read_done reply; 643 struct client_file find, *cf; 644 const int flags = O_NONBLOCK|O_RDONLY; 645 int error; 646 647 if (datalen < sizeof *msg) 648 fatalx("bad MSG_READ_OPEN size"); 649 if (datalen == sizeof *msg) 650 path = "-"; 651 else 652 path = (const char *)(msg + 1); 653 log_debug("open read file %d %s", msg->stream, path); 654 655 find.stream = msg->stream; 656 if ((cf = RB_FIND(client_files, &client_files, &find)) == NULL) { 657 cf = file_create(NULL, msg->stream, NULL, NULL); 658 RB_INSERT(client_files, &client_files, cf); 659 } else { 660 error = EBADF; 661 goto reply; 662 } 663 if (cf->closed) { 664 error = EBADF; 665 goto reply; 666 } 667 668 cf->fd = -1; 669 if (msg->fd == -1) 670 cf->fd = open(path, flags); 671 else { 672 if (msg->fd != STDIN_FILENO) 673 errno = EBADF; 674 else { 675 cf->fd = dup(msg->fd); 676 if (~client_flags & CLIENT_CONTROL) 677 close(msg->fd); /* can only be used once */ 678 } 679 } 680 if (cf->fd == -1) { 681 error = errno; 682 goto reply; 683 } 684 685 cf->event = bufferevent_new(cf->fd, client_read_callback, NULL, 686 client_read_error_callback, cf); 687 bufferevent_enable(cf->event, EV_READ); 688 return; 689 690 reply: 691 reply.stream = msg->stream; 692 reply.error = error; 693 proc_send(client_peer, MSG_READ_DONE, -1, &reply, sizeof reply); 694 } 695 696 /* Run command in shell; used for -c. */ 697 static __dead void 698 client_exec(const char *shell, const char *shellcmd) 699 { 700 const char *name, *ptr; 701 char *argv0; 702 703 log_debug("shell %s, command %s", shell, shellcmd); 704 705 ptr = strrchr(shell, '/'); 706 if (ptr != NULL && *(ptr + 1) != '\0') 707 name = ptr + 1; 708 else 709 name = shell; 710 if (client_flags & CLIENT_LOGIN) 711 xasprintf(&argv0, "-%s", name); 712 else 713 xasprintf(&argv0, "%s", name); 714 setenv("SHELL", shell, 1); 715 716 proc_clear_signals(client_proc, 1); 717 718 setblocking(STDIN_FILENO, 1); 719 setblocking(STDOUT_FILENO, 1); 720 setblocking(STDERR_FILENO, 1); 721 closefrom(STDERR_FILENO + 1); 722 723 execl(shell, argv0, "-c", shellcmd, (char *) NULL); 724 fatal("execl failed"); 725 } 726 727 /* Callback to handle signals in the client. */ 728 static void 729 client_signal(int sig) 730 { 731 struct sigaction sigact; 732 int status; 733 734 if (sig == SIGCHLD) 735 waitpid(WAIT_ANY, &status, WNOHANG); 736 else if (!client_attached) { 737 if (sig == SIGTERM) 738 proc_exit(client_proc); 739 } else { 740 switch (sig) { 741 case SIGHUP: 742 client_exitreason = CLIENT_EXIT_LOST_TTY; 743 client_exitval = 1; 744 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 745 break; 746 case SIGTERM: 747 client_exitreason = CLIENT_EXIT_TERMINATED; 748 client_exitval = 1; 749 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 750 break; 751 case SIGWINCH: 752 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 753 break; 754 case SIGCONT: 755 memset(&sigact, 0, sizeof sigact); 756 sigemptyset(&sigact.sa_mask); 757 sigact.sa_flags = SA_RESTART; 758 sigact.sa_handler = SIG_IGN; 759 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 760 fatal("sigaction failed"); 761 proc_send(client_peer, MSG_WAKEUP, -1, NULL, 0); 762 break; 763 } 764 } 765 } 766 767 /* Callback for client read events. */ 768 static void 769 client_dispatch(struct imsg *imsg, __unused void *arg) 770 { 771 if (imsg == NULL) { 772 client_exitreason = CLIENT_EXIT_LOST_SERVER; 773 client_exitval = 1; 774 proc_exit(client_proc); 775 return; 776 } 777 778 if (client_attached) 779 client_dispatch_attached(imsg); 780 else 781 client_dispatch_wait(imsg); 782 } 783 784 /* Dispatch imsgs when in wait state (before MSG_READY). */ 785 static void 786 client_dispatch_wait(struct imsg *imsg) 787 { 788 char *data; 789 ssize_t datalen; 790 int retval; 791 static int pledge_applied; 792 793 /* 794 * "sendfd" is no longer required once all of the identify messages 795 * have been sent. We know the server won't send us anything until that 796 * point (because we don't ask it to), so we can drop "sendfd" once we 797 * get the first message from the server. 798 */ 799 if (!pledge_applied) { 800 if (pledge( 801 "stdio rpath wpath cpath unix proc exec tty", 802 NULL) != 0) 803 fatal("pledge failed"); 804 pledge_applied = 1; 805 } 806 807 data = imsg->data; 808 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 809 810 switch (imsg->hdr.type) { 811 case MSG_EXIT: 812 case MSG_SHUTDOWN: 813 if (datalen != sizeof retval && datalen != 0) 814 fatalx("bad MSG_EXIT size"); 815 if (datalen == sizeof retval) { 816 memcpy(&retval, data, sizeof retval); 817 client_exitval = retval; 818 } 819 client_exitflag = 1; 820 client_exit(); 821 break; 822 case MSG_READY: 823 if (datalen != 0) 824 fatalx("bad MSG_READY size"); 825 826 client_attached = 1; 827 proc_send(client_peer, MSG_RESIZE, -1, NULL, 0); 828 break; 829 case MSG_VERSION: 830 if (datalen != 0) 831 fatalx("bad MSG_VERSION size"); 832 833 fprintf(stderr, "protocol version mismatch " 834 "(client %d, server %u)\n", PROTOCOL_VERSION, 835 imsg->hdr.peerid & 0xff); 836 client_exitval = 1; 837 proc_exit(client_proc); 838 break; 839 case MSG_SHELL: 840 if (datalen == 0 || data[datalen - 1] != '\0') 841 fatalx("bad MSG_SHELL string"); 842 843 client_exec(data, shell_command); 844 /* NOTREACHED */ 845 case MSG_DETACH: 846 case MSG_DETACHKILL: 847 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 848 break; 849 case MSG_EXITED: 850 proc_exit(client_proc); 851 break; 852 case MSG_READ_OPEN: 853 client_read_open(data, datalen); 854 break; 855 case MSG_WRITE_OPEN: 856 client_write_open(data, datalen); 857 break; 858 case MSG_WRITE: 859 client_write_data(data, datalen); 860 break; 861 case MSG_WRITE_CLOSE: 862 client_write_close(data, datalen); 863 break; 864 case MSG_OLDSTDERR: 865 case MSG_OLDSTDIN: 866 case MSG_OLDSTDOUT: 867 fprintf(stderr, "server version is too old for client\n"); 868 proc_exit(client_proc); 869 break; 870 } 871 } 872 873 /* Dispatch imsgs in attached state (after MSG_READY). */ 874 static void 875 client_dispatch_attached(struct imsg *imsg) 876 { 877 struct sigaction sigact; 878 char *data; 879 ssize_t datalen; 880 881 data = imsg->data; 882 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 883 884 switch (imsg->hdr.type) { 885 case MSG_DETACH: 886 case MSG_DETACHKILL: 887 if (datalen == 0 || data[datalen - 1] != '\0') 888 fatalx("bad MSG_DETACH string"); 889 890 client_exitsession = xstrdup(data); 891 client_exittype = imsg->hdr.type; 892 if (imsg->hdr.type == MSG_DETACHKILL) 893 client_exitreason = CLIENT_EXIT_DETACHED_HUP; 894 else 895 client_exitreason = CLIENT_EXIT_DETACHED; 896 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 897 break; 898 case MSG_EXEC: 899 if (datalen == 0 || data[datalen - 1] != '\0' || 900 strlen(data) + 1 == (size_t)datalen) 901 fatalx("bad MSG_EXEC string"); 902 client_execcmd = xstrdup(data); 903 client_execshell = xstrdup(data + strlen(data) + 1); 904 905 client_exittype = imsg->hdr.type; 906 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 907 break; 908 case MSG_EXIT: 909 if (datalen != 0 && datalen != sizeof (int)) 910 fatalx("bad MSG_EXIT size"); 911 912 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 913 client_exitreason = CLIENT_EXIT_EXITED; 914 break; 915 case MSG_EXITED: 916 if (datalen != 0) 917 fatalx("bad MSG_EXITED size"); 918 919 proc_exit(client_proc); 920 break; 921 case MSG_SHUTDOWN: 922 if (datalen != 0) 923 fatalx("bad MSG_SHUTDOWN size"); 924 925 proc_send(client_peer, MSG_EXITING, -1, NULL, 0); 926 client_exitreason = CLIENT_EXIT_SERVER_EXITED; 927 client_exitval = 1; 928 break; 929 case MSG_SUSPEND: 930 if (datalen != 0) 931 fatalx("bad MSG_SUSPEND size"); 932 933 memset(&sigact, 0, sizeof sigact); 934 sigemptyset(&sigact.sa_mask); 935 sigact.sa_flags = SA_RESTART; 936 sigact.sa_handler = SIG_DFL; 937 if (sigaction(SIGTSTP, &sigact, NULL) != 0) 938 fatal("sigaction failed"); 939 kill(getpid(), SIGTSTP); 940 break; 941 case MSG_LOCK: 942 if (datalen == 0 || data[datalen - 1] != '\0') 943 fatalx("bad MSG_LOCK string"); 944 945 system(data); 946 proc_send(client_peer, MSG_UNLOCK, -1, NULL, 0); 947 break; 948 } 949 } 950